Annular Cooling Flow Passage for Gas Turbine Thermal Management
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Solution Overview
Problem
Gas turbine engine components, particularly in the high-pressure sections, face excessive thermal loading due to insufficient cooling, with existing ventilation systems failing to effectively manage the high temperatures and recirculation of airflow, which can lead to material limitations and potential damage.
Innovation Solution
An annular cooling flow passage system is introduced, featuring dual inlets and internal walls that guide airflow in a reverse and forward direction within the passage, enhancing cooling efficiency by coalescing flows and minimizing frictional heating, with the first inlet airflow directed to cool the outer wall before mixing with the secondary, hotter airflow from the boundary layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air is extracted from the boundary layer of the main gas path to cool the high pressure turbine, then cooling is provided to the turbine components, but the extracted air has higher temperature than the main gas path which has a detrimental impact on engine components
Solution Approach 1:
The cooling system is divided into separate pathways: one for extracting cooler air from the main gas path and another for extracting hotter boundary layer air. These segmented flows are then recombined in the annular passage to create an optimized cooling flow that reduces thermal loading on components.
Solution Approach 2:
The annular cooling flow passage is nested within the ventilation cavity structure, with internal walls positioned inside the annular passage to guide and direct the cooling flows. This nested arrangement allows efficient use of space while maintaining separate flow paths that can be merged.
2Productivity
If a ventilation cavity is provided between the high pressure compressor and high pressure turbine, then cooling flow can be supplied to the turbine, but recirculation of airflow occurs which causes frictional heating and reduces cooling efficiency
Solution Approach 1:
The harmful recirculating flow is extracted and removed from the system by providing outlet openings in the internal walls that discharge the cooling flow directly to the turbine. This prevents the recirculation loop that causes frictional heating and improves overall cooling efficiency.
Solution Approach 2:
Instead of allowing the cooling flow to recirculate back to the compressor inlet, the system inverts the flow path by directing it through outlet openings to the turbine. This reversal eliminates the harmful recirculation and uses the cooling flow where it is most needed.
3Reliability
If cooling air is supplied to high pressure turbine components, then thermal loading is reduced, but the components must still withstand temperatures in excess of 1500°C which approaches material limitations
Solution Approach 1:
Cooling air is supplied to the turbine components in advance, before the hot combustion gases reach them. The cooling flow is established in the annular passage and directed onto the turbine components through outlet openings, creating a protective thermal barrier that allows the components to withstand the subsequent exposure to 1500°C+ combustion temperatures.
Solution Approach 2:
A cushioning layer of cooling air is established beforehand on the turbine components, creating a thermal protection layer that cushions the components against the extreme combustion temperatures. This prior cushioning allows the use of materials with lower melting points while still withstanding the high operating temperatures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system significantly reduces thermal loading on high-pressure turbine components by optimizing airflow direction and mixing, thereby increasing cooling efficiency and preventing recirculation-induced heating, thus extending the operational lifespan of engine parts.
Implementation Method 1
the annular cooling flow passage has at least one internal wall for guiding an airflow from the first inlet towards an airflow from the second inlet, such that the airflow from the first and second inlets coalesce within the annular flow passage
Implementation Method 2
the system significantly reduces thermal loading on high-pressure turbine components by optimizing airflow direction and mixing, thereby increasing cooling efficiency
Implementation Method 3
preventing recirculation-induced heating
Data Source
AI summary
This invention concerns a system for cooling components in a gas turbine engine, the gas turbine engine including a compressor for driving a primary gas flow to a combustor and a turbine arranged to be driven by combustion gases from the combustor, wherein the system includes: an annular cooling flow passage arranged for fluid communication between the compressor and the turbine, the flow passage having a first inlet arranged to receive gas from the primary gas flow downstream of compressor, and a second inlet located upstream of the first inlet, wherein the annular cooling flow passage has at least one internal wall for guiding airflow from the first inlet towards the airflow from the second inlet, the airflow from the first and second inlets coalesce within the annular flow passage prior to passing along the passage in a direction from the compressor to the turbine.